This invention relates to an abrasive saw blade, and more particularly to a diamond abrasive saw blade which uses a diamond abrasive matrix on its outer perimeter and which is useful for the dry cutting of concrete or other masonry materials.
Generally, a diamond abrasive concrete or masonry saw blade has a flat, circular plate which serves as a substrate or body for the saw blade. An enlarged rim of a diamond particle matrix is secured (e.g., welded) to the outer periphery of the circular plate. This diamond particle/matrix rim comprises a suitable matrix, such as a suitable synthetic resin material or a suitable metal (e.g., copper), having numerous diamond particles of a predetermined size uniformly distributed throughout the matrix. This diamond abrasive matrix rim is of a predetermined depth such that the circumference of the rim is greater than the diameter of the circular plate. Further, the rim has a width or thickness from one side face thereof to the other greater than the thickness of the plate. The diamond abrasive/matrix rim may be secured to the outer periphery of the plate in any suitable manner, such as by laser or electron beam welding.
Typically, such prior art diamond abrasive saw blades are mounted on the drive shaft of a power driven saw and are driven at a relatively high rotational speed such that when the saw blade is brought into working engagement with the work to be cut (e.g., a slab of masonry or concrete), the partially exposed diamond particles on the outermost surfaces of the saw blade abrasively engage and cut into the work. With prior art diamond abrasive concrete saws, a stream of suitable cooling fluid (preferably water) is discharged onto the rotating saw blade, generally above the work and at the front end of the blade for the dual purpose of cooling the saw blade and of carrying away the small particles or chips of the work abrasively cut by the diamond particles.
In the construction of concrete highways or the like, concrete is oftentimes poured as a monolithic slab without traditional expansion joints at pre-determined intervals between separate slabs. It is now conventional to saw or cut the "green" or partially cured monolithic concrete slab at pre-determined intervals shortly after the concrete has hardened (i.e., about 6-16 hours after pouring of the concrete). For example, in a monolithic slab of a highway lane, the monolithic poured slab is partially cut in transverse direction at regular intervals (e.g., every 20-30 feet). The depth of these cuts may range about 2-4 inches for a slab having a thickness between about 8 and 12 inches. After partially cutting the monolithic slab along these prescribed transverse cuts, the slab will then crack along these predetermined transverse cuts. The predetermined cutting and cracking of the slabs along the lines of cutting prevents random cracking of slabs. After sawing, the grooves sawed in the slab are filled with a suitable filler/sealer material (e.g., an elastomeric type material) which prevents water from entering the groove and the crack and, in turn, prevents damage to the concrete caused by the freezing of water within the groove.
Further, in the localized repair of highways, it is oftentimes necessary to remove a portion of the pavement for the repair. This oftentimes necessitates sawing away of a portion of the old concrete highway to be repaired.
Typically, the saws utilized to cut such grooves in a concrete highway or to cut away parts of the highway for repair purposes, are large, self propelled saws. Such saws include a powerful engine which rotatably drives the saw blade at a high rotational speed with the rim of the saw being rotated at a high surface speed. Oftentimes the saw is power driven along a desired line of cutting at a predetermined speed or feed rate. The saw blade may be selectively raised and lowered with respect to the concrete to be cut.
As mentioned, such prior art diamond abrasive saws required the use of water or other fluid as a coolant for the saw blade and as a medium for carrying the chips of concrete cut by the diamond particles. This requirement of supplying such coolant water to the saw blade at a remote construction site presented a considerable expense, required a substantial capital investment, and consumed expensive labor.
The length of cutting typically realized, utilizing a prior art diamond abrasive blade in green concrete with the use of coolant water varied greatly, depending on the hardness of the aggregate in the concrete, the state of the fully uncured concrete, and the depth of the cut. For example, utilizing a prior art diamond abrasive saw blade having a diameter of 14 inches and having a diamond abrasive rim approximately 3/16 of an inch (0.187) inches wide and being driven by the saw at a rotational speed of about 2600-3300 rpm (i.e., at a surface speed of about 9,525-12,087 feet per minute) will yield about about 4,000-12,000 lineal feet of cutting. Feed rates of up to about 17 feet per minute may be achieved.
In concrete or other masonry materials having a relatively soft aggregate, an abrasive saw blade (as opposed to a diamond blade) may be utilized. Such abrasive typically have fiberous substrate fibers or the like with suitable abrasive particles of silicon carbide or the like held in place on the fiberglass substrate by suitable synthetic resin which impregnates the fiberglass substrate and which securely holds the particles in place. Typically, such an abrasive saw blade is utilized without a cooling fluid. However, such abrasive saw blades are not able to cut concrete having a hard aggregate.
There has been a long standing need for a concrete or masonry saw blade which will readily cut hard aggregate concrete or masonry materials at rates of feed comparable to prior art diamond saw blades, but without the necessity of supplying coolant water to the saw.